Washington D.C. [USA], April 2 : Diabetic patients, especially women, who work at night, may have more symptoms of depression than those who sleep and wake-up early, regardless of the quality of their sleep, finds a study.
According to researchers, people with Type-2 diabetes, who are "night owls" and prefer the evening for activity report, have more symptoms of depression than those who are early to bed and early to rise.
The results are scheduled to be presented at the Endocrine Society's 99th annual meeting in Orlando, Florida.
"These findings are important because depression is common in patients with Type-2 diabetes," said lead investigator Sirimon Reutrakul from Mahidol University's faculty of medicine in Bangkok, Thailand.
"Also, previous studies have shown that untreated depression is related to worse patient outcomes, including diabetes self-care, blood glucose control and diabetes complications," Reutrakul added.
The team wanted to study people with Type-2 diabetes, who have an increased risk of depression, to learn whether a later chronotype, or preference for evening activity, was independently associated with greater depression symptoms.
They studied diabetic patients from two different geographic regions: Chicago and Thailand. The U.S. group consisted of 194 patients, 70 percent of whom were women. Similarly, in the Thai group, women comprised 67 percent of 282 patients. All the participants answered questionnaires regarding symptoms of depression, sleep quality and preferred times for activity and sleep.
For both groups, those who preferred the evening reported more depression symptoms than did those with a morning preference.
This result remained even after the researchers adjusted their statistical analyses for sleep quality, age, sex and other factors that could affect depression.
Their findings support an association between circadian regulation and psychological functioning in patients with Type-2 diabetes.
"We need further research to explore a combination of interventions that help with circadian timing, such as light therapy and melatonin," she said.
"Learning more about the relationship between depression and circadian functioning might help us figure out strategies to improve physical and mental health for patients with diabetes," Reutrakul explained.